Corrosion Inhibition Efficiency of Biosynthesized Silver Nanoparticles Using Citrus aurantium Peels Extract

Corrosion is a detrimental persistent industrial conundrum that can cause the failure of operating equipment and weakening of construction assemblies, thus threatening the lives of humans, and accelerating the consumption of the natural metals reservoirs. In this study, we deployed green silver nanoparticles (AgNPs) as corrosion inhibitors for mild steel. Citrus aurantium peels aqueous extract (CAPE) mediated the bio-reduction of silver ions (Ag⁺) into silver nanoparticles (AgNPs) under optimized experimental conditions. The prepared nanoparticles were comprehensively characterized by various techniques for size, morphology, optical properties, crystallinity, and elemental composition. Phytochemical analysis showed that the plant extract is rich in phenolic compounds that facilitated the formation of metallic silver from Ag⁺ ions. The anticorrosion properties of CAPE and CAPE-AgNPs for mild steel in 0.5 M HCl were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The biosynthesized CAPE-AgNPs were more efficient than CAPE in slowing down corrosion with inhibition efficiency of 70% attained at 1000 ppm of the inhibitor. CAPE and CAPE-AgNPs acted as mixed-type corrosion inhibitors with dominance over the cathodic reaction. Fitting the experimental data into different isotherms demonstrated that the corrosion inhibition was an endothermic process that took place through physical adsorption. CAPE-AgNPs significantly reduced pitting and localized damage on the metal surface. These findings highlighted the utility of CAPE-AgNPs as efficient corrosion inhibitors in different industrial settings.